Stable flooring products and method of making same

ABSTRACT

The present invention is directed to an article of manufacture suitable for flooring utilization which comprises a flooring panel adapted for interlocking connection with another correspondingly adapted flooring panel, such article having at least one edge with one or more elements formed such that they are operative to mate with one or more reciprocal elements associated with said other correspondingly adapted flooring panel, which article further comprises a frictional backing material that is non-adhesive in respect of, but exhibits resistance to movement with respect to, a surface underlying the article when in contact with the surface; and a method of making same.

PRIORITY INFORMATION

The priority of U.S. Application Ser. No. 61/702,992, filed Sep. 19, 2012, is claimed, the subject matter of such provisional application being incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to flooring products, including laminate flooring panels such as floor tiles, adapted so that adjacent units of flooring products are capable of interlocking with one another.

BACKGROUND OF THE INVENTION

There is increasing sensitivity in the flooring industry to safety and durability concerns relating to flooring products, including the minimization of movement of such flooring products after installation, while concomitantly enhancing durability and maintaining an attractive performance profile. One particularly pressing dilemma is utilization of highly desirable interlocking mechanisms, such as tongue-and-groove systems, for connecting units of flooring products together without shifting and/or movement of those units when in contact with the underlying surface being covered.

Examples of products having interlocking elements appear in: U.S. Pat. Nos. 6,584,747, 7,516,587 and 6,684,592; U.S. Patent Publication Nos. 2008/0138560 and 2005/0144880; and EP Patent Publication Nos. 0,843,763 and 1,024,234, each of which is hereby incorporated by reference. In one interlocking mechanism, flooring products (e.g., a floor panel) may contain an edge profile on at least two opposite edges with a tongue element on one edge and a groove element on the other. By way of explanation, panels are interconnected via a tongue-and-groove joint with the tongue on one edge of a first panel inserted into the groove on an associated edge of a second panel. A dilemma arises because though tongue-and-groove or other interlocking joinder is highly desirable in some ways, at the same time it can impede attainment of stability and traction of the flooring panels on an underlying surface. Thus, on the one hand, interlocking connections are sturdy, effective and convenient. However, on the other, securing panels by means of interlocking connection can also lead to a stability shortfall. This is especially so if the interlocking connection is, as customary, effected only on two opposite sides of a rectangular product, a common approach, since to interlock on all four sides introduces undesirable difficulty. This erodes the performance profile of interlocking flooring products because product units interconnected on only two sides as aforesaid can shift when not anchored to the surface thereunder. There is the aesthetic disadvantage of creeping misalignment, and typically an overlapping of adjacent panels at their edges. The cumulative effect of even small shifts over an expanse of panels can cause stacking and thus unevenness at panel interfaces. This is unsightly. And, even more important, shifting poses a risk of injury should there be product movement underfoot or uneven surfaces due to the stacking of panels, each of which may lead to a fall or the like.

To secure the flooring product adequately one approach has been to fix the flooring product to its underlayer with adhesive. But, the benefit of using interlocking mechanisms, namely, easier installation due to the omission of adhesive, is lost. Furthermore, use of adhesive can be troublesome as removal of the product is laborious, and the product is induced to conform to imperfections in the underlying surface.

The foregoing is true of not only natural as well as synthetic flooring materials, but significantly also laminate flooring. Laminate flooring has become particularly popular because it provides several advantages over natural floor materials, such as lower cost, ease of replacement, and lighter weight, and also advantages over synthetic materials, such as improved durability, wear-resistance and sound-damping capacity. Moreover, a particularly appealing aspect of laminate flooring is its potential for reduced thickness vis-à-vis other types of floor panel. That is to say thicker panels have two important drawbacks, they require more material to produce, and they weigh more. These factors increase production and transportation costs, which are then passed on to the consumer in the form of higher floor panel prices. In addition, with thicker flooring products come environmental consequences, such as increased fuel consumption attendant upon transporting greater volumes and weights of thicker flooring products, and disposal difficulties. (The aforementioned problems complicate both compliance with government regulations and conformity with voluntary standards which entitles one to publicize that fact for competitive advantage.) Accordingly, laminate products are increasingly attractive, and yet the interconnection of same via interlocking elements is likewise afflicted by the problems applicable to more traditional products.

It would be a substantial advance in the art if natural, synthetic and especially laminate flooring products featuring interlocking mechanisms but having mitigated susceptibility to instability and non-uniformity underfoot, could be achieved.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the invention to provide a safer interlocking flooring product.

It is a further object of the invention to provide an interlocking flooring product in which instability and non-uniformity underfoot are mitigated.

It is another object of the invention to provide an interlocking flooring product comprising frictional backing material that mitigates movement of the product against the surface upon which it rests.

It is yet another object of the invention to provide an interlocking flooring product that is resistant to movement against a surface upon which it rests but without being adhesively secured to such surface.

It is yet another object of the invention to provide an interlocking flooring product that is easier for a consumer to install.

It is an even further object of the invention to provide a method of making such a flooring product.

These and other objects are attained through practice of the invention as follows.

In a first aspect the present invention is directed to an article of manufacture suitable for flooring utilization, which comprises a flooring panel adapted for interlocking connection with another correspondingly adapted flooring panel, such article having at least one edge with one or more elements formed such that they are operative to mate with one or more reciprocal elements associated with said other correspondingly adapted flooring panel, which article further comprises a frictional backing material that is non-adhesive in respect of, but exhibits resistance to movement with respect to, a surface underlying the article when in contact with the surface.

In another aspect the present invention is directed to a method of making an article of manufacture suitable for flooring utilization, said article including a flooring panel adapted for interlocking connection with another correspondingly adapted flooring panel, by reason of said article's having at least one edge with one or more elements formed such that they are operative to mate with one or more reciprocal elements associated with said other correspondingly adopted flooring panel, which method comprises providing a frictional backing material on the flooring panel, said frictional backing material being non-adhesive in respect of, but resistant to movement with respect to, a surface underlying the article when in contact with the surface.

The expressions “adapted”, “formed” and “associated with”—when utilized herein concerning interlocking elements that connect flooring products (e.g., panels)—are to be understood as encompassing elements for conjoining adjacent flooring products (such as flooring panels), whether the interlocking elements are produced integral with the flooring panel, or made separately and attached to the panel thereafter—directly or indirectly through one or more intermediate components. Thus, a flooring panel can for instance be fashioned using a mold which accommodates the panel's precursor materials, such mold including portions that allow for production of the desired interlocking elements as an undivided extension of the flooring panel at one or more of its edges. On the other hand, it is conceivable that the interlocking elements can be produced in a separate operation and then appended to the panel after production but before use. Accordingly, the flooring products and methods of the invention are not in their broadest embodiments exclusive of either version of such interlocking elements.

The present invention has significant benefits over the current state of the art. Thus, the desirable efficiencies, aesthetics and convenience attendant upon installation, use and removal of interlocking flooring products non-adhesively applied are preserved, but without the instability—and especially movement—that ordinarily accompany such non-adhesively applied interlocking products. Furthermore, the damaging effects on flooring product of exposure to moisture and alkalinity may likewise be mitigated by the invention, as the frictional backing material can be resistant to passage thereof.

More specifically, practice of the invention confers substantial advantages. With the invention not only are the undesirable effects of interlocking connections—e.g., movement of the panels and cumulative stacking—reduced but also the attractive performance characteristics of interlocking mechanisms are maintained. This includes preservation of the favorable “optics” resulting from avoidance of adhering flooring product to an underlying surface.

It is integral to our invention that the mitigation of undesirable floor-product movement and other instability is not accompanied by an appreciable fall-off in the desirable characteristics of interlocking flooring. The success of our innovative approach to lessening movement and other instability would not have been suggested consistent with conventional practice and therefore was not foreshadowed.

The advantages of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an article of manufacture in accordance with the invention.

FIG. 2 is a cross-sectional view of an article of manufacture comprising a laminate flooring panel in accordance with the invention.

FIG. 3 is a schematic view in perspective of an article of manufacture illustrating the interlocking feature in accordance with the invention.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

A central aspect of the invention is the discovery that provision, on an interlocking flooring product such as a panel, of frictional backing material resistant to movement against a surface on which the panel is to be laid is effective to mitigate undesired instability of the panel during and after installation. The invention extends to all manner of flooring products, whether of natural or synthetic material or a combination thereof, including laminate panels and especially such panels having a reduced thickness in accordance with the invention disclosed in U.S. patent application Ser. No. 13/114,873, filed May 24, 2011, the subject matter of which is incorporated herein by reference. Preferably, panels are provided with a frictional backing material that exhibits a coefficient of friction, typically a coefficient of static or kinetic friction, vis-à-vis the constituent material making up the surface on which the panel is laid. That coefficient is typically greater than a coefficient between an underlying surface and a panel not backed in accordance with our invention. The coefficient is therefore indicative of an amount of friction sufficient to accomplish the objectives of our invention, including effecting the mitigation of movement, preferably by at least 50 percent, especially by at least 75 percent, in comparison with movement that would otherwise occur absent practice of the invention.

By way of explanation, the friction relevant to our invention is dry friction which resists relative lateral motion of two solid surfaces in contact. The two regimes of dry friction are ‘static friction’ between non-moving surfaces, and kinetic friction (sometimes called sliding friction or dynamic friction) between moving surfaces. The coefficient of friction (“COF”) is a dimensionless scalar value which describes the ratio of the force of friction between two bodies and the force pressing them together. The COF depends on the materials used; for example, ice on steel has a low COF, while rubber on pavement has a high COF. For surfaces at rest relative to each other the coefficient of static friction is the parameter of interest. For surfaces in relative motion the relevant parameter is the coefficient of kinetic friction. The COF is an empirical measurement—it has to be measured experimentally, and cannot be found through calculations. Rougher surfaces tend to have higher effective values. Both static and kinetic coefficients of friction depend on the pair of surfaces in contact; for a given pair of surfaces, the coefficient of static friction is usually larger than that of kinetic friction; in some instances the two coefficients are equal. While it is often stated that the COF is a “material property,” it is better categorized as a “system property.” Unlike true material properties (such as conductivity, dielectric constant, yield strength), the COF for any two materials depends on system variables like temperature, velocity, atmosphere and also what are now popularly described as aging and deaging times as well as on geometric properties of the interface between the materials. Of course, static friction and kinetic friction are for purposes of our invention related, but not the same. Accordingly, the instant sliding occurs, static friction is no longer applicable—the friction between the two surfaces is then called kinetic friction. The maximum value of static friction, when motion is impending, is sometimes referred to as limiting friction, although this term is not used universally. It is also known as traction. Kinetic (or dynamic) friction occurs when two objects are moving relative to each other and rub together (like a sled on the ground). Kinetic friction is now understood, in many cases, to be primarily caused by chemical bonding between the surfaces; nevertheless, in many other cases roughness effects are dominant, for example in rubber to road friction. On balance, static friction is logically the more significant parameter, as it is typically the case that preventing a panel from moving at all is better than having it translate to any degree; nevertheless, once the movement threshold is crossed, an enhanced resistance to the extent of such movement is advantageous.

From the foregoing it is believed apparent that the COF—whether static or kinetic—is determined by the frictional backing material as it interacts with the underlying surface material. However, the dimensionless coefficient is usefully (though not necessarily) defined as being at least 0.3 (static), 0.2 (kinetic), preferably at least 0.5 (static), 0.3 (kinetic). More specifically, the coefficient can be defined as lying within the range of 0.3 to 1.3 (static) and 0.2 to 1.2 (kinetic) irrespective of the particular combination of frictional backing material and underlying surface material. The range is preferably 0.5 to 1.3 (static) and 0.3 to 1.1 (kinetic). It follows that the frictional backing material for flooring products must be selected with a view toward their respective interactions with the particular underlying surface.

The frictional backing material can be natural or synthetic substance(s), or a combination of natural and synthetic substances. It is typically of a polymeric nature. Illustrative types of frictional backing materials are polyvinyl chloride (PVC), polyethylene, polypropylene, polyurethane, epoxy resin, acrylic, latex, rubber, neoprene, and coated or natural textiles.

The frictional backing material is selected in view of the substance on which the flooring product will be laid. That substance is typically concrete, but it can be other substances such as wood, rubber, plastic, asphalt, etc. The respective constituents of the frictional backing material and underlying surface are coordinated to obtain the desired coefficient.

The articles of manufacture encompassed by our invention are now described in greater detail with reference to the figures of drawing. The individual layer thicknesses described hereinafter are intended to be illustrative and not limiting.

In advantageous embodiments, the product and method of our invention are such that the underside of the flooring panel and the frictional backing layer are adjoined. If the panel is non-laminate, the cross-section is as depicted in FIG. 1. On the other hand, if the panel is of laminate structure, there are multiple layers above the frictional backing material, as depicted in FIG. 2. Generally speaking, the multiple layers of a laminate can include one or more of a balance layer, an embossing layer, and first and second stabilizing layers. A wear layer is adjoined directly to a surface of the design layer, with a protective layer on the surface of the wear layer opposite that adjoined to the design layer, and the structural backing layer is adjoined to an opposite surface of the design layer through intermediate layers comprising said second stabilizing layer, said balance layer, said first stabilizing layer, and said embossing layer, either in that order or a different one, its being understood that the intermediate layers are optional and that any one or more of them can be omitted.

With specific reference to FIG. 1, there is shown a uni-layer panel 10, a surface upon which the panel rests (typically below the panel) 20, and a frictional backing material 30 interposed between them. Uni-layer panel 10 comprises an interlocking mechanism including reciprocal components 10A and 10B. Specifically, interlocking component 10A of a first panel 10 is configured to lock with interlocking component 10B of a second panel 10. As to FIG. 2, there are shown five layers (not shown to scale) within the panel. From top to bottom, they are: a protective coat layer, a wear layer, a design layer, an embossing layer, and a structural backing layer. These layers are respectively elements 110, 120, 130, 140 and 150 in FIG. 2. The panel includes an interlocking mechanism (not shown for purposes of simplicity); for example, like that of components 10A and 10B of FIG. 1. The underlying surface is element 160 and the frictional backing material is element 170. The frictional backing material 170 may be adhered to the structural backing layer 150.

Protective coat layer 110 functions as the primary mechanism for creating sheen along with acting as a first-line barrier against wear. The protective coat layer may be adjusted to provide for different sheens, such as high gloss or low gloss. In a preferred embodiment, the protective coat has a pre-production thickness of approximately 0.085-0.115 mm. In another embodiment, the protective coat has a pre-production thickness of less than 0.144 mm.

Design layer 130 provides the primary visual component of the floor tile. The layer is polyvinyl chloride or other flooring design polymer, and is typically in the form of imprinted film or otherwise decorated with suitable adornment to give the flooring a desired appearance, such as a wood design. It is generally located under the transparent wear layer so that the primary visual displayed is the adornment on the design layer. In a preferred embodiment, the design layer has a pre-production thickness of approximately 0.05-0.13 mm. In another embodiment, the design layer has a pre-production thickness of less than 0.16 mm.

Wear layer 120 is the primary protective layer and is located above the design layer 130. Although the protective coat layer initially provides shielding, it generally wears away after use. The wear layer provides long-term wear-resistance that guards against damage to the design layer. In a preferred embodiment, the wear layer has a post-production thickness of approximately 0.45-0.55 mm. In another embodiment, the wear layer has a post-production thickness of less than 0.688 mm.

Embossing layer 140 helps provide a more realistic visual, for example, by adding the appearance of texture. In one embodiment, when the flooring panel contains a discrete balance layer, embossing layer 140 has a pre-production thickness of approximately 0.95-1.05 mm. In another embodiment, when the flooring panel contains a discrete balance layer, embossing layer 140 has a pre-production thickness of less than 1.31 mm. In another embodiment, when the flooring panel does not contain a discrete balance layer, embossing layer 140 has a pre-production thickness of approximately 2.25-2.35 mm. In another embodiment, when the flooring panel does not contain a discrete balance layer, embossing layer 140 has a pre-production thickness of less than 2.94 mm.

Structural backing layer 150 underlies the design layer and provides balance for deformations or pressure to the wear layer. The structural backing layer 150 is the least porous layer, and this decreased permeability retards liquids from entering the flooring from below. In a preferred embodiment, structural backing layer 150 has a pre-production thickness of approximately 0.95-1.05 mm. In another embodiment, the structural backing layer 150 has a pre-production thickness of less than 1.31 mm. In a preferred embodiment, the frictional backing material 170 is adhered or attached to the structural backing layer 150.

A further and important function of both frictional backing material 30 (FIG. 1) and frictional backing material 170 (FIG. 2) is that in good embodiments of the invention they are composed of material that is resistant to the passage of aqueous fluid. Thus, the flooring is protected by the backing material to a helpful degree from the potentially damaging effects of moisture entrapped thereunder; and, in those instances where the flooring panel is a laminate comprising a backing layer that is of relatively low permeability, the frictional backing material augments an already existing resistance to liquid. Furthermore, since the backing material is virtually unreactive with alkaline species, any alkaline content in seepage or any other incursion by an alkaline substance is impeded. In such manner, flooring can be more effectively protected from the destructive influences of alkaline presence as well.

In still another aspect of the invention, there are illustrated in FIG. 3 various examples of interlocking mechanisms 310, 320 and 330.

It will be appreciated that, in the context of the invention, a “layer” is “proximate” one surface or another of the “design layer” of our laminate floor panel if it is close or near to—though not necessarily immediately adjacent—the design layer. There can be one or more other layers interposed between the “layer” in question and the “design layer”, as depicted in the figures of drawing included herein. As is further clear from the figures of drawing, a layer “proximate” one surface of the design layer is closer to that surface of the design layer than it is to the opposite surface of the design layer. The wear layer and the structural backing layer are each “proximate” its corresponding surface of the design layer.

The flooring product of our invention can be made by a method involving location of the frictional backing material on all or part of the underside (i.e., the side of the flooring panel intended to be in contact with the surface to be covered). Location can be implemented by affixing the backing material through applying heat and pressure to the assemblage of the panel and frictional backing material. Because the thickness and character of the panel can vary from one embodiment to another, differing amounts of heat and pressure will need to be applied respectively to the combinations of different embodiments. The frictional backing material can also be affixed to the underside of the flooring panel with adhesive. Alternatively, location can be implemented by covering all or part of the flooring panel's underside with backing material that can be for instance deposited and cured on the underside. In any event, once in possession of the teachings herein, those of ordinary skill in the art will be able by routine and empirical extrapolation, without experimentation rising to the level of further invention, to determine the appropriate conditions for treating the precursor assemblage to yield the article of manufacture of the invention. It goes almost without saying that the application of heat and pressure or other curing conditions are preferably effective to secure the frictional backing material to the panel, but sufficiently controlled so that the heat and/or pressure (optionally in combination with one or more other prevailing conditions) or other curing conditions are not of an extent or a duration so as to damage any of the constituent materials whereby the flooring product or any of its properties sought is materially compromised.

Accordingly, as described above, various embodiments of an interlockable flooring panel with a suitable frictional backing material, while maintaining quality and structural integrity, are provided.

The foregoing components of the present invention described as making up the various elements of the invention are intended to be illustrative and not restrictive. Many suitable components that would perform the same or similar functions as the components described are intended to be embraced within the scope of the invention. Such other components can include, for example, components developed after the development of the present invention. 

What is claimed is:
 1. An article of manufacture suitable for flooring utilization, which comprises a flooring panel adapted for interlocking connection with another correspondingly adapted flooring panel, said article having at least one edge with one or more elements formed such that they are operative to mate with one or more reciprocal elements associated with said other correspondingly adapted flooring panel, which article further comprises a frictional backing material that is non-adhesive in respect of, but exhibits resistance to movement with respect to, a surface underlying the article when in contact with the surface.
 2. An article of manufacture as defined in claim 1, wherein said at least one edge of the article is provided with either a tongue or groove element operative to interlock with a reciprocal tongue or groove element on said other correspondingly adapted flooring panel.
 3. An article of manufacture as defined in claim 1, wherein the backing material has a coefficient of static friction of from 0.3 to 1.3.
 4. An article of manufacture as defined in claim 1, wherein the backing material has a coefficient of static friction of from 0.5 to 1.3.
 5. An article of manufacture as defined in claim 1, wherein the backing material has a coefficient of kinetic friction of from 0.2 to 1.2.
 6. An article of manufacture as defined in claim 5, wherein the backing material has a coefficient of kinetic friction of from 0.3 to 1.1.
 7. An article of manufacture as defined in claim 1, wherein the frictional backing material includes one or more polymeric substances.
 8. An article of manufacture as defined in claim 7, wherein each of the polymeric substances is selected from the group consisting of polyvinyl chloride (PVC), polyethylene, polypropylene, polyurethane, epoxy, acrylic, latex, modified or encapsulated rubber, and neoprene.
 9. A method of making an article of manufacture suitable for flooring utilization, said article including a flooring panel adapted for interlocking connection with another correspondingly adapted flooring panel, by reason of said article's having at least one edge with one or more elements formed such that they are operative to mate with one or more reciprocal elements associated with said other correspondingly adapted flooring panel, which method comprises locating a frictional backing material on the flooring panel, said material being non-adhesive in respect of, but resistant to movement with respect to, a surface underlying the article when in contact with the surface.
 10. A method as defined in claim 9, wherein the backing material has a coefficient of static friction of from 0.3 to 1.3.
 11. A method as defined in claim 10, wherein the backing material has a coefficient of static friction of from 0.5 to 1.3.
 12. A method as defined in claim 9, wherein the backing material has a coefficient of kinetic friction of from 0.2 to 1.2.
 13. A method as defined in claim 12, wherein the backing material has a coefficient of kinetic friction of from 0.3 to 1.1.
 14. A method as defined in claim 9, wherein said at least one edge of the article said at least one edge of the article is provided with either a tongue or groove element operative to interlock with a reciprocal tongue or groove element on said other correspondingly adapted flooring panel.
 15. A method as defined in claim 9, which comprises locating the frictional backing material on the flooring panel via affixing the material to the panel by means of applying an effective amount of heat and pressure to the material and panel, affixing the material to the panel with adhesive, or affixing the material to the panel by curing the material while it is on the panel.
 16. A method as defined in claim 9, wherein the frictional backing material includes one or more polymeric substances.
 17. A method as defined in claim 16, wherein each of the polymeric substances is selected from the group consisting of polyvinyl chloride (PVC), polyethylene, polypropylene, polyurethane, epoxy, acrylic, latex, modified or encapsulated rubber, and neoprene. 